Lost oil pressure in a fresh build

[TKFireman]

So I disassembled everything, grill, radiator, electric fan, AC compressor, alternator, power steering pump, fuel pump, all hoses, then after remembering the hard way that the water pump has to come off before the harmonic balancer, everything came off this morning, including the timing cover. Both galley plugs behind the timing set are there and sealed, thats not the problem, can't see the upper ones without pulling the intake.

So I think to myself, what to do next. I think "hey, lets pull a valve cover and see if oil is getting to the rockers" then immediately after that "hey dummy, you pulled the timing cover, too late" So I put the timing cover back on with a few bolts and the old gasket, hoping it would seal good enough and it did, 5 psi oil pressure on the drill, no leaks. I pulled the driver side rocker cover and ran the drill for a good 2 minutes straight with around 5 psi oil pressure, never saw a drop come out of any of the push rods to any of the rockers.....not good.....

So I guess I will keep disassembling, I'm thinking intake next, which I'm going to drop some coolant into the oil pan when I pull it, but shouldn't hurt the engine to prime it with a little coolant mixed with the oil will it? I'd like to prime it after pulling the intake and see if I can see anything else.

[TKFireman]

Pretty sure I found the problem, which I was not expecting because I honestly did not notice a difference in engine sound, I reckon I'm just deaf or something.....Now.....What all do I need to replace/check? Obliviously all new push rods, those are the factory original ones with spacers under the rockers to make up length. Should have gone with new hardened ones when I rebuilt.

Should I buy a tool and measure for new ones, go original length and use shims again, which may be easier. Any company ya'll recommend to order push rods from? What was the probable cause for this? Too much HP/RPMS for 30 year old stockers or something I did wrong during assembly?

[tufcj]

I had the same thing happen in my CJ when one of the rocker bridge bolts broke.

Why spacers under the rockers? Was a lot milled from the heads or block? They will usually tolerate a .010-.015 total milling without shims. What's the closed pressure on the valve springs? How much lift on the cam?

Could be too heavy of springs. Could be the valve retainer hitting the valve guide. Could be simple metal fatigue. I'd do a leak down test to be sure the valve hasn't hit the piston and bent, check springs and valve guide to retainer clearance. If that all checks out, throw new pushrods in it and run it.

Bob
tufcj

[TKFireman]

Thanks for the suggestions. Springs are stock replacements that's all I can tell you about them. Spec sheet from machine shop said deck height is 9.190" which is .015" shorter than stock I think. Heads where surfaced by .010" for a total of .025" taken off.

Machinist said to install push rods and tighten to zero lash, or just where the lifter was not pushed down at all and measure the distance between the rocker and head. He said the distance needed to be no more than .030" and no less that .015." My gaps where around .040" for most cylinders so the shims went in, which is what the machinist suggested. Odd thing was cylinders #3 and #5 were right at .030" so I did not use shims on those cylinders, intake or exhaust. Broken push rod was #5 intake.

Cam is a Melling MTA-1, here are the specs
----------------INT----EXH
Cam lift---------.281---.296
Valve Lift-------.450---.474
Lobe Ctr--------105----115
SAE duration----280----289
.050 duration----204----214

SAE Timing
BTC-- ABC-- BBC-- ATC
30 ---- 70 ---74 --- 35

.050 Timing
BTC-- ABC-- BBC-- ATC
-3 --- 27 --- 42 --- -8

[tufcj]

With that cam, there shouldn't be a retainer to guide problem. Stock compression? Stock style pistons? I had flat top pistons in a 304 that had to have reliefs cut with just a .468" lift cam. You might want to look at the top of that piston with a bore scope.

Bob
tufcj

[TKFireman]

the pistons are. 030" over stock compression. I don't have a bore scope but I think my neighbor has a leak down tester. I think that would be a good idea. With the intake off it would be obvious if the intake valve is damaged and leaking at all. Thanks for the suggestions.

[390spirit]

glad you found the problem.



i nailed it with my first post LOL not saying you over reved it but i had the same thing happen to me LOL

Norm

[TKFireman]

You did hit it on the first post 390spirit. It is possible I over reved it, cam is rated for 1500-4500 rpm. Pretty sure I hit 5000+ a time or two. I got to remeber I have a CJ7 and not a race car sometimes. I ordered new push rods made by comp. hopefully will be able to put it back together, test everything and fire it up next week.

[TKFireman]

I borrowed a cylinder leak down tester this morning and ran a test on the #5 cylinder, which is where the intake push rod broke. It passed and none of the air coming out of it was coming out of the intake port on the head or the exhaust.

I went ahead and cleaned everything up and re-installed the timing cover, water pump, harmonic balancer and the alternator. I'll leave the AC compressor and power steering pump off just to keep them out of the way while installing the intake. This afternoon I plan to pull the rockers and old push rods, clean up the intake, and maybe open the bolt holes on it just a little, it was a PITA to put on on the stand, gonna be worse in the engine bay. Opening those holes a fuzz won't hurt anything that I can see, or am I wrong?

I'm debating on whether or not to install the intake, which then I could install the grill, radiator and everything else, or wait until the push rods get here and install the intake after putting the valve train together, any opinions on that?

[390spirit]

i personally would do the intake after the valvetrain, but either way will work